A solution of NaOH was obtained by dissolving 5.6g of NaOH pellets in 100cm^3 of water. What is the concentration of resulting solution?
mols NaOH = grams/molar mass
M = mols NaOH/L soln.
Huh? What's the answer?
To find the concentration of the resulting solution, we need to calculate the amount of NaOH dissolved in 100 cm³ of water.
The dissolved amount of NaOH can be calculated using the formula:
Amount (in mol) = mass (in g) / molar mass (in g/mol)
The molar mass of NaOH is the sum of the atomic masses of Na (sodium), O (oxygen), and H (hydrogen). From the periodic table, the atomic masses are:
Na: 22.990 g/mol
O: 16.000 g/mol
H: 1.008 g/mol
So, the molar mass of NaOH is:
Na: 22.990 g/mol
O: 16.000 g/mol
H: 1.008 g/mol
Adding these together gives us:
22.990 + 16.000 + 1.008 = 39.998 g/mol ≈ 40.00 g/mol (rounded to two decimal places)
Now, we can calculate the amount of NaOH in moles:
Amount (in mol) = 5.6 g / 40.00 g/mol = 0.14 mol
Since the solution is made up of 100 cm³ of water, the concentration can be calculated using the formula:
Concentration (in mol/cm³) = amount (in mol) / volume (in cm³)
Concentration (in mol/cm³) = 0.14 mol / 100 cm³ = 0.0014 mol/cm³
Therefore, the concentration of the resulting NaOH solution is 0.0014 mol/cm³.